Non Stress Test – An Update

Abstract

Non stress test is a time tested, convenient and reliable test of antenatal fetal surveillance. It accurately predicts those fetus that do not require acute or premature obstetric intervention and thereby prevents pregnancies from being subjected to unnecessary iatrogenic risks and avoids unnecessary medical, financial and emotional burden. The principle of non stress test is that the heart rate of a fetus with adequate oxygenation and normal neurological response will temporarily accelerate with fetal movement. Loss of reactivity is commonly associated with a fetal sleep cycle but may result from any cause of central nervous system depression, fetal acidosis or maternal drug intake and requires further evaluation for an extended period or evaluation with other techniques like biophysical profile or amniotic fluid testing or umbilical artery Doppler study as per the overall clinical scenario. A correctly performed NST, using standard technique with proper interpretation may be of great value in planning further management.